How to manage cotton in the late stage? Nine reminders to keep in mind

Cotton has now entered the boll-opening stage, the final growth stage. Throughout September, the upper bolls are still continuing to grow and fill out. From now until harvest is completed in late October, there are still more than 50 days, and if management is relaxed, significant losses can still occur.

(1) Do not relax mentally when it comes to late-stage management, and especially do not think that because there are not many bolls, high yields are impossible, and therefore be unwilling to invest further. If you can keep more than 40,000 bolls per mu and let them grow and open well, you can harvest four to five hundred jin of seed cotton per mu. I downloaded 6 new nationally approved cotton varieties from our province, and their yield performance in national regional trials and production trials was all four to five hundred jin of seed cotton per mu. The trial fields cannot be called poor, and the management cannot be called bad; it should be said that four to five hundred jin is currently the upper-middle level. If you can reach 50,000 bolls per mu, the prospects are even better. Many people easily fall into the bad habit of loving to manage the better fields more and becoming more discouraged with the worse ones, and only at the very end regret that they should not have relaxed late-stage management and lost the yield that was already within sight. This point is very important.

(2) For cotton fields suffering premature senescence caused by potassium deficiency, if there are still upright green leaves on the upper part or some cotton plants are only mildly prematurely senescent, spray one more 2% potassium sulfate fertilizer solution.

(3) For cotton fields that are still relatively dense, you can remove the large leaves on the main stem in the middle and lower parts and the empty branches, so the cotton field is ventilated and lets light through, which helps the already mature bolls lose water and crack, open normally, and reduces rotten bolls increased by continued rainfall.

(4) If conditions permit, pick the already blackened bolls, shell the cotton, and dry it in the sun, which can reduce losses.

(5) For cotton plants that have fallen over or been bent down because of many bolls set on the middle and upper parts and can no longer be propped upright, you can spend one or two minutes tying them up, which can save twenty or thirty bolls, and it is worth it.

(6) In September, damage from tobacco whitefly (sometimes commonly called whitefly) may still occur, and when it breaks out it can dry up all cotton leaves and cause yield reduction. Do not wait until there are so many insects that they become a disaster before controlling them; as soon as you find insects active in dense areas, start applying pesticide. Tests have shown that bifenthrin has a relatively good control effect.

(7) In ordinary cotton fields, by September 5 at the latest, remove all flower buds that have not yet opened and the tips, to promote faster growth and development of the upper young bolls and minimize post-frost cotton.

(8) In September, air humidity becomes lower and soil evaporation increases. If there is no rainfall afterward, autumn drought may still occur in late September. If there are relatively many upper bolls and watering is fairly convenient, you can apply one watering to boost the bolls; otherwise, it is too regrettable to reduce yield because of drought. This item applies to high-yield fields.

(9) For cotton fields that need ethephon for ripening, the first spraying should not be too heavy, and paraquat and similar substances must not be sprayed. Around October 1, depending on the weather and how dense the cotton field is, it is advisable to spray in two applications to promote ripening. After the first application, first let most cotton leaves gradually turn yellow to promote the transfer of nutrients to the bolls, and then an abscission layer forms at the petiole and the leaves fall off. Be sure not to kill the cotton leaves all at once with one application; the second application then promotes the bolls to crack and open.